Cat c15 Sdp rebuild help

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by dustinbrock, Jun 8, 2018.

  1. dustinbrock

    dustinbrock Road Train Member

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    Truck was pushing coolant so I just pulled my head off today and have a few questions..

    I believe I found a bad spot on one of the fire rings, it looks a little wider on the one side and honestly looks to me like it crushed a little more than the rest... took off spacer plate and going to clean everything up then check the liner heights to see if anything is off.

    I have the cat sled dial, I have the cat bolt, washers and nylon washers to check it properly.

    Engine was rebuilt, complete out of frame a year ago and only worked a few months before having issues.... deck and counter bores were not cut as the mechanic said they were within spec. I know he was in the middle of nowhere and didn't have the tools to cut them and suspect he may be full of it.

    Now what I'm wondering about, my spacer plate is covered in surface rust on the deck side.... all over it. Is this normal? The brown o ring that goes in the spacer plate was found in my water pump a few months back, we assumed it was a spare but I only see a o ring on the top side of the spacer plate but not the bottom.... I will double check on the deck tomorrow morning though as I brought the plate home to clean up.

    Pistons and liners are mint and the head looks brand new with no cracks, going to pressure test the head for internals.

    How do you guys clean the spacer plate up and the deck? Wire brush, grinding disc, sand paper etc... spacer plate was new during rebuild so I'm hoping I can reuse it but I wanna mic it and make sure it's true/even.

    Thanks alot gents, appreciate any input or ideas you may have.

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    Last edited: Jun 8, 2018
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  2. Goodysnap

    Goodysnap Medium Load Member

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    I use a twisted cup wire brush on the deck,head and spacer plate. Absolutely nothing abrasive. Detail hard spots with a hand carbide scraper if needed.

    Cat has recently added applying a layer of liquid gasket sealant to the thin metal gasket which might help keep the rust at bay on the bottom of the spacer plate. Mic the spacer plate to see if stock or undersize. An undersized plate may have just been winged in it if your sceptical the previous builder even measured the height.
     
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  3. dustinbrock

    dustinbrock Road Train Member

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    What is a acceptable variance in the spacer plate? .001 difference acceptable?

    Nevermind about this question, spacer plate is .336 to .337 with big low spots, getting a new one.
     
    Last edited: Jun 9, 2018
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  4. Rubber duck kw

    Rubber duck kw Road Train Member

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    Have you ever used the 3m green scrubber discs for head surface or is that too abrasive?
     
  5. dustinbrock

    dustinbrock Road Train Member

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    Used a sled guage to check out the deck to see if it was warped or not and to see how bad the water jackets spots were slotted out. The water jackets grooves are .003 on some.

    To me, this deck looks warped bad but I'm no pro, this is my first engine I've opened up myself so I thought I'd ask you guys here. I did not prep the deck, just cleaned it off real quick of any crap....
     
  6. Goodysnap

    Goodysnap Medium Load Member

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    The 3M bristle disc are nice tools given the proper technique in the correct place. I will admit I have some in my box, but dont use them often. Keep them flat and dont push real hard or use them on edge because they still do contain abrasive and will remove machining marks from sealing surfaces. They do last a long time and are worth the money, sure. In the wrong hands they can cause some damage. Most of today's engine manufacturers don't endorse using anything abrasive on gasket surfaces for this reason that it causes imperfections in the sealing surface that may cause leaks and or the abrasives in the tool contaminate the oil and cause bearing failure. This is why the brown cookies are a big nono on any engine.

    Wire tools are much better option, IMO. But you must spend the money on high quality stainless twisted wire wheels. Wieler are nice wheels that last and dont fly apart and get wires stuck in your forehead. Keep the rpm's low......20k diegrinder is way to fast. Metabo paddle grinder is where it's at. I also keep Red scotch brite pads on hand as most o-ring type joints just need a scrubbing and wiped off for a new seal. The surfaces often dont have to be polished to a mirror finish to reseal properly.
     
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  7. dustinbrock

    dustinbrock Road Train Member

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    I can very visibly see gaps with a straight edge, looks like the engine's coming out to go to the machine shop.....
     
  8. spsauerland

    spsauerland Road Train Member

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    Agree 100%. I really like the super scraper brand carbide tip scrapers. I still use the 7448 ulra fine hand pads. You want it clean, not remove material. I finish wipe everything down with laquer thinner til my microfiber rags stay clean.
     
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  9. superhauler

    superhauler Super Crusty

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    If you have that kind of gaps then yeah deck the block deck the head if it is a good one and buy the thinner spacerplate. That will get your liner protrution to .006. Check the liner lips for uneven wear also. You may have to replace some liners if uneven lips.
     
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  10. dustinbrock

    dustinbrock Road Train Member

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    Engine has maybe 4 months of use since complete rebuild so I am hoping flanges are good although I suspect I may have one cracked..

    Wonder if you good dummy down the reason why you say I should get the thinner spacer plate? Will cutting the deck make it so I have to use th thinner one, or would I need shims after cutting the deck and the smaller spacer plate will make it so I don't have to shim?

    (Head new during last rebuild 4 months ago and looks mint)
     
    Last edited: Jun 9, 2018
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